It's from a Bristol Fighter (see attachment). The "G" and "N" numbers are production numbers on British manufactured propellers. They can be used to determine the date of production, but I don't have that list. You might look through some posts here where Bob Gardner has listed production dates from some other props and get a rough idea of when yours was manufactured based on those numbers. Unfortunately I don't think there's a good way to search for those other than looking through his posts and trying to view ones that may apply to British props.

Maybe this link will get you to Bob's posts, and you might even try sending him a private message to inquire. He hasn't posted here in quite a while.